All-In-One Fertiliser vs Dry Salts Guide: Cost and Control

Walk into any Singapore aquarium shop and you’ll see two camps of planted-tank keepers: one buying SGD 25 bottles of all-in-one liquid, the other ordering 100 g packets of KNO3 from a Carousell chemist. All in one fertiliser vs dry salts comes down to a trade between convenience and control, with cost differences that compound dramatically over a year. This comparison from Gensou Aquascaping at 5 Everton Park breaks down the maths, the dosing flexibility, and which approach suits which planted-tank temperament.

What Each Format Actually Contains

All-in-ones are pre-mixed liquids combining macros (N, P, K) and micros (Fe and trace metals) at fixed ratios. Tropica Specialised, Seachem Flourish, ADA Brighty K, and Aqua Rebell Makro Basic NPK each lock you into one nutrient profile. Dry salts let you mix exactly what your tank needs: KNO3 for nitrogen, KH2PO4 for phosphate, K2SO4 for extra potassium, MgSO4 for magnesium, and CSM+B for traces. The dry approach means seven labelled bottles instead of one, but every ratio is yours to set.

Cost Per Litre Dosed

A SGD 28 bottle of Tropica Specialised at 300 ml dosed at 6 ml weekly per 200 litres lasts 50 weeks — roughly SGD 0.56 per dose, SGD 29 per year. The same nutrient delivery from dry salts: KNO3 at SGD 8/kg yields 130 weekly doses (SGD 0.06 per dose), KH2PO4 at SGD 12/kg yields over 1500 weekly doses, CSM+B at SGD 15/100 g lasts a year. Total annual cost: SGD 8-12. The dry route saves around SGD 200/year on a 200-litre EI tank.

Dosing Flexibility

All-in-ones lock NPK ratios. If your tank needs more N but less P (common when bioload runs heavy from fish), you cannot adjust without overdosing the rest. Dry salts let you bump KNO3 alone, drop KH2PO4 to half, or pull potassium up independently. For tanks chasing red plant colour, the ability to run lean phosphate while keeping nitrogen up matters — and only dry salts allow it cleanly.

The Convenience Curve

All-in-ones win on day-one ease. Open bottle, draw out marked dose, squeeze into tank, done in 15 seconds. Dry salts demand a kitchen scale, mixing bottles, dechlorinated water for stock solutions, and labelled containers in the fridge. After the initial setup the daily dose is identical — pump 5-10 ml from a marked bottle. The barrier is the first hour of mixing, which puts off most casual hobbyists.

Singapore Availability

All-in-ones stock at every shop: Tropica Specialised, Seachem Flourish, ADA Brighty K and Mineral, Aqua Rebell Makro/Mikro, and the local Bangkok-imported Top Aquatic line. Find them in the fertilisers section. Dry salts are trickier — KNO3 falls under controlled chemicals so reputable Carousell and Shopee suppliers ship from Malaysia or Thailand, with delivery times of 5-10 days. K2SO4, KH2PO4 and MgSO4 are unregulated and arrive next-day.

Shelf Life and Storage

Sealed all-in-ones last 24 months but degrade once opened — iron oxidises within six months even in dark bottles. Refrigerate after opening to extend to a year. Dry salts last indefinitely sealed in airtight containers; KH2PO4 absorbs humidity in Singapore’s climate so silica gel sachets in the storage jar are mandatory. Pre-mixed dry-salt stock solutions need refrigeration and citric acid to prevent iron precipitation.

Best Use Cases for Each

All-in-ones suit nano tanks under 60 litres, low-tech setups dosed weekly, travel-prone keepers, and beginners through their first year. Dry salts suit anyone running a 100-litre+ high-tech tank, anyone targeting specific plant outcomes (red intensity, carpet density, slow-stem control), and anyone bothered by SGD 25-30 monthly fertiliser bills. The crossover point is roughly 100 litres or six months of EI experience.

Hybrid Approaches

Many experienced keepers run dry salts for macros (KNO3, KH2PO4) and an all-in-one micro mix (Tropica Premium or Seachem Flourish trace) to skip the iron-stability headache. This costs about SGD 60/year while keeping macro flexibility. A dosing pump with three channels handles macro, micro and root-zone supplements separately — the gold standard for serious planted setups.

Decision Framework

Pick all-in-ones if you value time over money, run tanks under 80 litres, or prefer not to handle dry chemicals. Pick dry salts if your tank is over 100 litres, you want red plant colour, or you have run all-in-ones for six months and feel limited. Pick hybrid if you have already burned a SGD 30 bottle of trace mix on iron precipitation. The aquascaping tools section at Gensou stocks measuring syringes for either route.

Related Reading

• Estimative Index Dosing Walkthrough Guide
• Lean Dosing Weekly Schedule Guide
• Dosing Pump vs Manual Comparison Guide
• Root Tab Brand Comparison Guide
• Aquarium Iron Dosing Guide